SOLUTION: you bicycle 15 miles at 21 mph, then 20 miles at 18 mph, and finally 30 miles at 12. how do i find the average speed? do i just add each of the speeds and divide by 3? or is there

Question 813170: you bicycle 15 miles at 21 mph, then 20 miles at 18 mph, and finally 30 miles at 12. how do i find the average speed? do i just add each of the speeds and divide by 3? or is there something else i need to do with the miles?
Answer by josmiceli(19441) (Show Source): You can put this solution on YOUR website!
Average speed is always ( total distance traveled ) / ( total time spent traveling )
It is not an average of several average speeds
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1st part of trip:

-------------
2nd part:

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3rd part:

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The total distance traveled is mi
The total time is hrs
You can find the common denominator, or just
use decimal equivilants

hrs
------------------
mi/hr

The average speed is 15.0275 mi/hr
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You can check this

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